What are the different types of acne and how are they managed?

Types of Acne and Management

Classification of Acne Types

Acne vulgaris is classified into distinct morphologic types—comedonal, papulopustular, and nodular—with severity graded as mild, moderate, or severe based on lesion count, distribution, and presence of scarring. 1

Primary Acne Types

• Comedonal acne presents with open comedones (blackheads) and closed comedones (whiteheads) without significant inflammation 1
• Papulopustular acne features inflammatory papules and pustules, ranging from mild (few lesions) to severe (numerous widespread lesions) 1, 2
• Nodular/nodulocystic acne involves deep, painful nodules and cysts that carry high risk for permanent scarring 1, 3

Important Acne Mimicker

• Pityrosporum folliculitis (fungal acne) presents with monomorphic truncal papules and pustules that are uniform in appearance, pruritic, and lack comedones—this requires antifungal therapy, not standard acne treatment 4
• Microbiologic testing with KOH preparation or fungal culture should be performed when patients present with uniform truncal papules to diagnose this condition 4

Severity Assessment

• Use the Investigator Global Assessment (IGA) or Physician Global Assessment (PGA) scale consistently to grade severity on a 5-point scale: clear, almost clear, mild, moderate, and severe 1, 5
• Always evaluate for scarring, post-inflammatory hyperpigmentation, and psychosocial impact—these factors warrant more aggressive treatment regardless of lesion count 5, 6

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Treatment Algorithm by Acne Type and Severity

Mild Comedonal or Papulopustular Acne

Start with topical retinoid (adapalene 0.1-0.3% or tretinoin 0.025-0.1%) combined with benzoyl peroxide 2.5-5% applied once nightly as first-line therapy. 1, 5

• Adapalene is preferred because it can be applied simultaneously with benzoyl peroxide without oxidation concerns and lacks photolability restrictions, unlike tretinoin 5, 6
• Adapalene 0.1% is available over-the-counter, making it highly accessible 5
• Wait 20-30 minutes after washing before applying tretinoin to completely dry skin to minimize irritation 7
• Add azelaic acid 15-20% for patients with post-inflammatory hyperpigmentation, particularly those with darker skin tones 5
• Topical dapsone 5% gel is particularly effective for inflammatory acne in adult females and does not require G6PD testing 5

Moderate Papulopustular Acne

Add a fixed-dose combination topical antibiotic with benzoyl peroxide (clindamycin 1%/BP 5% or erythromycin 3%/BP 5%) to the retinoid + benzoyl peroxide regimen. 1, 5

• Never use topical antibiotics as monotherapy—this rapidly causes bacterial resistance 4, 5
• Fixed-combination products enhance compliance and prevent resistance development 5
• Salicylic acid 20-30% chemical peels can provide intensive treatment for resistant comedonal acne 5

Moderate-to-Severe Inflammatory Acne

Initiate triple therapy: oral antibiotic (doxycycline 100 mg daily or minocycline 100 mg daily) + topical retinoid + benzoyl peroxide. 1, 5

• Doxycycline is strongly recommended with moderate evidence; minocycline is conditionally recommended as an alternative 5
• Sarecycline is a newer tetracycline option with dosing advantages 5
• Limit systemic antibiotics to 3-4 months maximum to minimize bacterial resistance—this is a critical time limit 5, 6
• Always combine oral antibiotics with benzoyl peroxide to prevent resistance 4, 5
• Subantimicrobial-dose doxycycline (20 mg twice daily to 40 mg daily) has shown efficacy for moderate inflammatory acne 5

Severe Nodular/Nodulocystic Acne

Isotretinoin is the definitive treatment and should be initiated immediately for severe acne, as it is the only drug affecting all four pathogenic factors. 1, 5

• Standard dosing is 0.5-1.0 mg/kg/day targeting cumulative dose of 120-150 mg/kg 5
• Daily dosing is preferred over intermittent dosing 5
• Isotretinoin is also indicated for treatment-resistant moderate acne after 3-4 months of appropriate therapy, or any acne with scarring or significant psychosocial burden 5, 6
• Mandatory pregnancy prevention through the iPledge program is required for persons of childbearing potential 5, 6
• Monitor only liver function tests and lipids—CBC monitoring is not needed in healthy patients 5
• Population-based studies have not identified increased risk of neuropsychiatric conditions or inflammatory bowel disease with isotretinoin 5

Adjunctive Therapy for Large Nodules

• Intralesional triamcinolone acetonide 2.5-10 mg/mL provides rapid pain relief and inflammation reduction within 48-72 hours for individual large, painful nodules at risk of scarring 5, 6
• Oral corticosteroid therapy can provide temporary benefit in severe inflammatory acne while starting standard treatment 5

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Hormonal Therapy Options for Female Patients

Combined oral contraceptives (COCs) and spironolactone are effective hormonal therapy options for female patients with acne. 1, 5

• COCs reduce inflammatory lesions by 62% at 6 months and can be used as monotherapy or combined with topical agents 5, 3
• Spironolactone 25-200 mg daily is useful for hormonal acne patterns, premenstrual flares, or those who cannot tolerate oral antibiotics 5, 6
• No potassium monitoring is needed in healthy patients without risk factors for hyperkalemia taking spironolactone 5, 6

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Maintenance Therapy After Clearance

Continue topical retinoid monotherapy indefinitely after achieving clearance to prevent recurrence. 5, 6

• Reduce to 2-3 times weekly for long-term maintenance 6
• Benzoyl peroxide can be continued as maintenance therapy 5, 6

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Special Considerations and Pitfalls

Fungal Acne (Pityrosporum Folliculitis)

• Never treat pityrosporum folliculitis with antibiotics—this worsens the condition 4
• First-line treatment requires topical azole antifungals or oral antifungals for extensive or resistant cases 4

Antibiotic Resistance Prevention

• Never use topical or oral antibiotics as monotherapy—resistance develops rapidly without concurrent benzoyl peroxide 4, 5, 6
• Never extend oral antibiotics beyond 3-4 months without re-evaluation, as this dramatically increases resistance risk 5, 6
• Always combine benzoyl peroxide with any antibiotic therapy 4, 5

Retinoid Application

• Apply retinoids to completely dry skin 20-30 minutes after washing to minimize irritation 7
• Avoid applying retinoids to broken skin or areas with active wounds 5
• Use daily sunscreen with retinoids due to photosensitivity risk 5
• Traditional tretinoin formulations should not be applied simultaneously with benzoyl peroxide due to oxidation inactivating tretinoin 5
• Start with reduced frequency of application and concurrent emollients to mitigate initial irritation 5

Pediatric Considerations

• Topical adapalene, tretinoin, and benzoyl peroxide can be safely used in preadolescent children aged 9 years or older with acne 5
• Infantile acne and mid-childhood acne in children under age 9 are beyond the scope of standard guidelines 1

Testing Recommendations

• Routine microbiologic testing is not recommended for typical acne vulgaris 1, 4
• Consider testing for Gram-negative folliculitis in patients with eruptive uniform pustules to nodules in periorificial areas, particularly after prolonged tetracycline treatment 4
• Routine endocrinologic evaluation is not recommended for the majority of patients with acne 1
• Laboratory evaluation is recommended only for patients who have acne and additional signs of androgen excess (hirsutism, irregular menses, androgenetic alopecia) 1